Cars travel on an uncrowded highway that is usually jammed with traffic ahead of the Asia-Pacific Economic Cooperation (APEC) Economic Leaders' Meeting in Beijing, China, 3 Nov 2014.

A senior Beijing official said on Wednesday the city could consider implementing a daily odd-even car ban to clean the air, prompting hot public discussions. Since it is set to bring much trouble to the city’s five million drivers, policymakers must be cautious in introducing the move.

Li Shixiang, vice-mayor of Beijing, said that the city will study the feasibility of adopting an odd-even car plate system, in which cars will be banned on alternate days depending on whether their number plates end in odd or even numbers.

Local authorities currently ban vehicles one day a week, depending on the final digit of the license plate, with two numbers included each day.

Although Li’s comment does not necessarily mean the policy will finally be adopted, it is clear that policymakers are tempted to take such a move after the city had a taste of clean air and blue skies during the Asia-Pacific Economic Cooperation meeting earlier this month.

However, Beijing policymakers must be very cautious in introducing the policy since it will bring much trouble to local residents if it becomes a normal daily practice.

Beijing’s public transportation system has improved considerably in recent years, but it is still lags far behind public need. The bus system is notorious for lacking punctuality while the subway system is excessively crowded during peak times.

If adopted, the odd-even plate system means half of the city’s 5.37 million car owners will be put off the road. If services of the public transportation system cannot be further improved, the new policy will only backfire and lead to more public complaints.

Moreover, the effect of improving the quality of air by banning cars is dubious.